Drilling operations, and especially directional drilling operations, often utilize one or more tools for determining the position of a drill bit and for directing the drilling force of the drill bit. These tools are often placed within the drill string, near the drill bit, e.g., near or within a drill collar or a sub in the bottom hole assembly. To operate, these tools require a stable and secure fit within the drill string. To centralize and/or stabilize such tools within a tubular string, blades, fins, or similar protruding members can be affixed to the exterior of such tools. These fins are frequently made from materials used to dampen the shock and vibrations common near the bottom hole assembly, such as rubber, hard plastics, and/or similar pliable materials.
When these downhole tools are damaged or otherwise cease to function properly, or when the drill string becomes stuck in the wellbore, the downhole tools must be retrieved, e.g., through use of a wireline to pull the downhole tools to the surface. The fins or other protrusions affixed to the tools, which normally assist in the operation and stability of the tools, can become obstacles in removing the tools from the drill string, as these fins must often pass through restrictions in the drill string during the retrieval operation. Frequently, these fins provide the tool with a greater diameter than that of one or more restrictions within the drill string, hindering removal of the tool, or rendering the removal impossible.
Therefore, a need exists for apparatuses that can be placed within a drill string, or on a tool itself, for the purpose of shearing, trimming, and/or reducing fins or similar objects from downhole tools, with great stability and accuracy, to allow the tools to freely pass through restrictions in the drill string and, thus, be retrieved to the surface.
In addition, a need exists for methods for shearing, trimming, and/or otherwise reducing objects in a drill string, including materials such as fins on the body of objects, to allow the objects to pass through restrictions in the drill string, thus enabling retrieval thereof.
Further, a need exists for apparatuses and methods for shearing, trimming, and/or reducing the diameter of multiple retrievable tools, as these tools are removed from a drill string and retrieved to the surface.
The present embodiments meet these needs.